Bilbao welcome Atletico for the second leg on Wednesday evening trailing 1-0 from the first leg, but the home side are unbeaten at San Mames this season.
"Having not marked in the first leg, we know the penalty now. Atletico have only lost to Espanyol this season and even then by just one goal," he told reporters at a press conference.
"We have to try to score, if we can in the first minute. We can't come just to defend, we have to score and win."
The winner of the affair will face Real Madrid in the semi-finals.